1. Field
Aspects of embodiments of the present invention relate to a fuel cell stack.
2. Description of the Related Art
Fuel cells are devices that convert the energy of fuel into electric energy, in which a pair of electrodes—an anode and a cathode—are disposed with an electrolyte therebetween, hydrogen or a fuel gas containing hydrogen comes in contact with the anode (fuel electrode) and an oxide gas comes in contact with the cathode (air electrode), such that the devices generate electricity and heat through an electrochemical reaction of the fuel gas and the oxide gas, which are ionized in the process described above.
Fuel cell stacks have improved performance when the unit cells connected in series have the same voltage and current characteristics. However, when any one of the unit cells connected in series has a defect and the current and voltage characteristics change, the performance of the entire stack decreases, such that the entire stack should be replaced, even if one unit cell has a problem.